1. Field of the Invention
This invention relates to hydrogen storage materials and methods of producing the hydrogen storage materials.
2. Description of the Related Art
A wide variety of hydrogen storage materials have been proposed, and hydrogen storage materials having Mg as a base material, as one type of the various hydrogen storage materials, have been developed. While Mg is an excellent hydrogen storage material that is lightweight and has a high hydrogen storage capability of 7.6 mass %, its reaction temperature is as high as 350-400° C., which means that Mg cannot store or adsorb hydrogen at room temperature.
Japanese Patent Application Publication No. 2002-53926 (JP-A-2002-53926) discloses a hydrogen storage alloy powder in which Ni ultrafine particles are dispersed in Mg crystal grains. The disclosed alloy powder suffers from its slow hydrogen-adsorption speed at around room temperature and slow desorption speed at about 300° C.
Japanese Patent Application Publication No. 2004-156113 (JP-A-2004-156113) discloses a hydrogen storage alloy powder in which an intermetallic compound Mg2Ni is dispersed in a Mg matrix, and Japanese Patent Application Publication No. 2000-265233 discloses a hydrogen storage alloy in which an intermetallic compound Mg2Ni and Mg—Ni base ultrafine particles are dispersed in Mg crystal grains. These alloy materials also suffer from its slow hydrogen-adsorption speed at around room temperature and slow desorption speed at around 300° C.